PDC and colorectal carcinoma: Because the combined Ala:Leu ≥4.0 and Pro:Leu ≥3.0 showed high sensitivity for identifying primary‐specific PDC deficient subjects (see Section 3.1), we determined the number and distribution of subjects who were ≥ 99.9%ile for either Ala:Leu or Pro:Leu and who also fulfilled CRC by exceeding both AA ratios (145 subjects constituting ~0.12% of all specimens; Figure 3B green dots), with 51% of newborns were in the NICU at time of DBS collection and 75% were term newborns (early, full, and late).